<template>
    <div>
        <div>圆的半径{{ r }}</div>
        <div>圆的周长{{ r1 }}</div>
        <div>圆的面积{{ r2 }}</div>

        <button @click="r++">加一🌚</button>
         
    </div>
</template>

<script setup>
import { ref ,computed} from 'vue';



const r = ref(1)

const r1 = computed(()=>{
    return r.value*2*Math.PI
})

const r2 = computed(()=>{
    return r.value*r.value*Math.PI
})


</script>

<style lang="scss" scoped>

</style>